Everyone can tell a Nubian from a Norwegian, so why not divide
people into different races? That's the question explored in "The
Difference Between Us," the first hour of the series. This
episode shows that despite what we've always believed, the world's
peoples simply don't come bundled into distinct biological groups.
We begin by following a dozen students, including Black athletes
and Asian string players, who sequence and compare their own DNA
to see who is more genetically similar. The results surprise the
students and the viewer, when they discover their closest genetic
matches are as likely to be with people from other "races" as
their own.

Much of the program is devoted to understanding why. We look
at several scientific discoveries that illustrate why humans cannot
be subdivided into races and how there isn't a single characteristic,
trait - or even one gene - that can be used to distinguish all
members of one race from all members of another.

HUMAN VARIATION

Modern humans - all of us - emerged in Africa about 150,000 to
200,000 years ago. Bands of humans began migrating out of Africa
only about 70,000 years ago. As we spread across the globe, populations
continually bumped into one another and mixed their mates and
genes. As a species, we're simply too young and too intermixed
to have evolved into separate races or subspecies.

So what about the obvious physical differences we see between
people? A closer look helps us understand patterns of human variation:

In a virtual "walk" from the equator to northern Europe, we
see that visual characteristics vary gradually and continuously
from one population to the next. There are no boundaries, so
how can we draw a line between where one race ends and another
begins?

We also learn that most traits - whether skin color, hair
texture or blood group - are influenced by separate genes and
thus inherited independently one from the other. Having one
trait does not necessarily imply the existence of others. Racial
profiling is as inaccurate on the genetic level as it is on
the New Jersey Turnpike.

We also learn that many of our visual characteristics, like
different skin colors, appear to have evolved recently, after
we left Africa, but the traits we care about - intelligence,
musical ability, physical aptitude - are much older, and thus
common to all populations. Geneticists have discovered that
85% of all genetic variants can be found within any local population,
regardless of whether they're Poles, Hmong or Fulani. Skin color
really is only skin deep. Beneath the skin, we are one of the
most similar of all species.

Certainly a few gene forms are more common in some populations
than others, such as those controlling skin color and inherited
diseases like Tay Sachs and sickle cell. But are these markers
of "race?" They reflect ancestry, but as our DNA experiment
shows us, that's not the same thing as race. The mutation that
causes sickle cell, we learn, was passed on because it conferred
resistance to malaria. It is found among people whose ancestors
came from parts of the world where malaria was common: central
and western Africa, Turkey, India, Greece, Sicily and even Portugal
- but not southern Africa.

CONFRONTING OUR MYTHS ABOUT RACE

We have a long history of searching for innate differences to
explain disparities in group outcomes - not just for inherited
diseases, but also SAT scores and athletic performance. In contrast
to today's myth of innate Black athletic superiority, a hundred
years ago many whites felt that Black people were inherently sickly
and destined to die out. That's because disease and mortality
rates were high among African Americans - the cause was poverty,
poor sanitation, and Jim Crow segregation, but it was easier for
most people to believe it was a result of "natural" infirmity,
a view popularized by influential statistician Frederick Hoffman
in his 1896 study, Race Traits and Tendencies of the American
Negro.

Racial beliefs have always been tied to social ideas and policy.
After all, if differences between groups are natural, then nothing
can or should be done to correct for unequal outcomes. Scientific
literature of the late 19th and early 20th century explicitly
championed such a view, and many prominent scientists devoted
countless hours to documenting racial differences and promoting
man's natural hierarchy.

Although today such ideas are outmoded, it is still popular to
believe in innate racial traits rather than look elsewhere to
explain group differences. We all know the myths and stereotypes
- natural Black athletic superiority, musical ability among Asians
- but are they really true on a biological level? If not, why
do we continue to believe them? Race may not be biological, but
it is still a powerful social idea with real consequences for
people's lives.